1. Field of the Invention
The present invention relates to a semiconductor composite apparatus, a method for manufacturing the semiconductor composite apparatus, an LED head that employs the semiconductor composite apparatus, and an image forming apparatus that employs the LED head.
2. Description of the Related Art
FIGS. 20A and 20B illustrate the outline of a conventional semiconductor device disclosed in “M. Konagai et al., Journal of Crystal Growth 45(1978), PP 277-280.” Referring to FIG. 20A, a semiconductor composite device has a GaAs/hetero epitaxial structure in which a release layer 3002 is sandwiched between a GaAs substrate 3001 and a semiconductor film 3003. The release layer 3002 is a 5 μm Ga0.3Al0.7As layer. The semiconductor thin film 3003 has a GaAs epitaxial structure. Referring to FIG. 20B, the semiconductor film 3003 is immersed in hydrogen fluoride (HF) to etch away the release layer 3002, thereby separating the upper semiconductor film 3003 from the GaAs substrate 3001.
The semiconductor film 3003 separated from the GaAs epitaxial structure is then bonded onto, for example, an Si substrate, not shown. The flatness of surfaces that are to be bonded determines the bonding quality such as bonding strength and adhesion. Thus, it is important to make the bonding surfaces very flat, for example, the surface must have a nanoscale flatness. Further, this type of bonding is achieved by the use of Van der Waals' forces acting between the bonding surfaces of materials to be bonded. Therefore, in order that a strong force acts between the surfaces to be bonded together, the distance between the surfaces must be as short as nanometers. In addition, generally speaking, material elements are not necessarily exposed completely on their surfaces.
The surfaces to be bonded are often covered with, for example, an organic substance. Therefore, good bonding effect requires the bonding surfaces to be cleaned. Additionally, for achieving a sufficient bonding strength, activation of the surfaces to be bonded is sometimes required. Such surface treatment highly depends on the materials, and may be complex accordingly.